This site is supported by donations to The OEIS Foundation.

# User:Frank Ellermann

## Contents

Today editing existing sequences is far simpler than it used to be in 2002 based on the tricky internal format : Find the sequence, log in with your OeisWiki account, click edit, update say a broken link, optionally add an edit comment, click submit, and some minutes later I got an e-mail that the proposed modification was approved by an associate editor. Actually I found the how to after the fact.

[talk]

## Sequence of the Day for October 17

A019973: Decimal expansion of tangent of
 75°
(
 5π 12
 15°
(
 π 12
 3.732050807568877...
This number
 c = 2 + 2√  3
, one of the two roots of
 x 2 − 4x + 1 = 0
, is connected to the Lucas-Lehmer sequence via the formula
$a(n) = c^{(2^n)} + c^{-(2^n)}.$

## Fun stuff

Three punched cards (3*80 columns) minus a space in column 72 (3*1), the vital card serial numbers in columns 73..80 (3*8) for a re-sort if you ever drop the deck, minus the internal format columns %S, %T, %U followed by a space (3*3) yields 204, or roughly 200 columns for comma separated terms if they happen to fit nicely in the remaining 3*68 columns.

In 2012 an editor changed it to 260 including spaces, five years before RFC 8140 was published. The OEIS corrupted the IETF. Joke off, I didn't submit a sequence for over a decade, and now I wasted 60 columns for more terms in A293308.

## Known OEISwiki bugs and limitations

• Instant commons is a mechanism introduced in 2011 permitting MediaWiki projects to import resources from WikiMedia commons. It is documented on the MediaWiki wiki. If you see a red link instead of an image below it does not yet work here:
• The Wikidata project is a pure WikiMedia project, unlike Instant commons, and this wiki needs no d: interwiki prefix for plain links to Wikidata. But Property:P829 (en: OEIS ID) is interesting.
• Special:MyUploads (same idea as MyPage and MyTalk) shows uploads when a newer MediaWiki version is installed here.
• For huge images the thumbnail generator fails miserably.
• FANDOMWikia allows to embed `<rss>` feeds on a page, this is not yet possible here: wmflabs.org/catfood could be interesting to find new pages added to commons:category:OEIS.
• `<abbr title="abbreviation">ABBR</abbr>` does not yet work here, use {{abbr|abbreviation|ABBR}} to bypass this limitation also for acronyms:
XHTML test: `<abbr title="Encyclopædia of Integer Sequences">EIS</abbr>`
{{abbr}} test: EIS.
• HTML5 deprecated `<tt>`, but purists cannot yet replace it by `<kbd>xyzzy</kbd>` or `<samp>foobar</samp>` here.
• Parser function `{{nse:101}}` should (roughly) work like `{{anchorencode:{{ns:101}}}}`. At the moment only the latter is supported here and gives `Extras_talk`, while the former fails with Template:Nse:101.
• Syntax highlighting with `<source lang="matlab">` is not yet installed: `<source lang="rexx">numeric digits 500; say digits()</source>`
• The list of supported media types for Special:Upload does not yet include any video type, notably `.ogv` and WebM (`VP8` or `VP9` video with Vorbis or `OPUS` audio) are not yet allowed. JFTR, the upload size limit is 2 MB.
• The CC-BY-NC license used here is incompatible with the commons CC-BY-SA limits — whatever that means (IANAL), see my commons page hosted by Google.
• The short version of the OEIS movie available on YouTube cannot be embedded on OeisWiki pages, because
1. I got no permission to upload it as `.ogv` to commons due to the license incompatibility (see above),
2. without InstantCommons that would anyway not help here (see above), but might be nice on Wikipedia(s),
3. it also cannot be uploaded here — the 998KB are okay, but video MIME types are not allowed (see above),
4. the short version apparently does not yet exist on the OEIS proper (the pages above the OEIS wiki), and
5. even if it existed on OEIS proper the OEIS MediaWiki installation could consider it as external and refuse to treat it as embedded.
• As of October, 2017 the oldest secure legacy LTS MediaWiki version was 1.27.3 (April), anything older is insecure.